One message read: “China Merchants Bank will issue a high interest financing product starting from June 28th to 30th. The product will be 90 days with a 5.5% interest rate. Please call us now.”

A day later came another. “Warm reminder: The interest rate of yesterday’s product has been raised to 6%. (Product duration is 90 days). There is limited access to this product. First come first served.”

The offers are not coming from fly-by-night operators but some of China’s biggest banks. They are raising huge pools of cash to finance a relatively new and highly profitable sideline business: lending outside the scrutiny of bank regulators.